Underground residential electric and distribution systems have primary and secondary voltage cables direct-buried in trenches, usually at curbside. To maintain the watertight integrity of these systems, all cable connectors, including splices, are insulated watertight.
Advances in rubber technology have generated the development of EPDM rubber splice covers, which are now in common use. They have largely eliminated the use of tape and various compounds for insulating splices because of the considerable installed cost for these systems. The use of EPDM rubber splice covers substantially reduces such costs. Splice covers have also been applied over splices and cables by heat-shrinking. This not only requires expensive equipment at the site, but also means that the cover must be destroyed in order to have access to the splice. Accordingly, EPDM splice covers which are slidable along the cables and the splice itself are now in use.
The splice assemblies that are the subject of this invention are generally for use on cables rated up to 600 volts. A typical splice cover has an interference fit about the cables where the ends of the splice cover meet with the cables. The interior of the splice cover, however, normally does not present an interference fit with the splice, but commonly includes an air space between the interior of the splice cover and the splice itself.
While properly designed EPDM splice covers of the type discussed above provide consistent watertight assemblies, it is important that the splice cover be installed centrally with respect to the splice. This ensures that the sealing interfaces between the splice cover and the cable insulation at each end of the splice cover are adequate to provide the required watertight seals. If the splice cover is installed off-center to the point where the bearing interface at one end of the splice cover assembly is substantially reduced in length, its watertight integrity could be impaired, resulting in failure and an electrical outage.
Accordingly, it is an object of this invention to provide a positive means of centering splice covers about splices to avoid off-center assemblies.
A further purpose of the present invention is to provide a splice and splice cover having an increased area in the splice for efficient conductance of electricity at midpoint, where current transfer is effected.
Yet another object of the invention is to provide an increased area at the splice midpoint which allows for a reduction in the areas of the splice cable entrance cylinders. The outside diameter of splices most commonly used in underground wiring can, thereby, be reduced. This permits their installation using pocket-size tools which are convenient for one-man installations in narrow trenches.
Another object of this invention is to provide a splice and splice cover having efficient conduction of heat from the splice during current overloads.
These and other objects of the invention will become obvious from the following description taken together with the drawings.